Phosphorescent iridium complex with non-conjugated cyclometalated ligands, synthetic method of preparing the same and phosphorescent organic light emitting diode thereof

ABSTRACT

The present invention discloses a phosphorescent tris-chelated transition metal complex comprising i) two identical non-conjugated cyclometalated ligands being incorporated into a coordination sphere thereof with a transition metal, and one ligated chromophore being incorporated into the coordination sphere; or ii) one non-conjugated cyclometalated ligand forming a coordination sphere thereof with a transition metal, and two ligated chromophores being incorporated into the coordination sphere, wherein the metal is iridium, platinum, osmium or ruthenium, and the ligated chromophore possesses a relatively lower energy gap in comparison with that of the non-conjugated cyclometalated ligand, the latter afforded an effective barrier for inhibiting the ligand-to-ligand charge transfer process, so that a subsequent radiative decay from an excited state of these transition complexes will be confined to the single ligated chromophore. The architecture and energy gap of the ligated chromophore are suitable for generation of high efficiency blue, green and even red emissions.

This Application claims the benefit of U.S. Provisional Application No.60/877,603, filed on Dec. 29, 2006. The disclosure of this ProvisionalApplication is hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to iridium complexes, and moreparticularly to the phosphorescent iridium complexes with non-conjugatedcyclometalated ligands, synthetic method of preparing the same andphosphorescent organic light emitting diode thereof.

BACKGROUND OF THE INVENTION

Phosphorescent organic light emitting diodes (OLEDs) are under intensiveinvestigation because of their potential of achieving improved devicebrightness and performances. In contrast to the fluorescent emission,the electrophosphorescence of heavy metal complexes are easily generatedfrom both singlet and triplet excited states and, thus, the internalquantum efficiency can reach a theoretical level of unity, rather thanthe 25% inherent upper limit imposed by the formation of singletexcitons for the respective fluorescent counterparts. Thus, a great dealof effort has been spent on the second and third-row transition metalcomplexes, for developing highly efficient phosphors that can emit allthree primary colors. Despite of the elegant research on both red andgreen phosphors, there are only scatter reports on the room temperatureblue phosphors. The best known example is one Ir(III) complex named asFIrpic in the following, which has proved to be an excellent dopant forsky-blue phosphorescent OLEDs. Further improvements were made bysubstituting picolinate with other ancillary ligands such as pyridylazolate ligand to afford derivative complexes FIrpyz or FIrtaz shown inthe following. These modifications have produced a hypsochromic shift of˜10 nm versus the emission of FIrpic; however, significant lowering ofQ.Y. was noted in some cases, which have hampered the fabrication of thetrue-blue phosphorescent OLEDs.

In theory, one has to consider some critical design in achieving thehigher efficient blue phosphorescence. One possibility is to increasethe MLCT contribution in the lowest lying triplet manifold. The directinvolvement of non-bonding, metal d_(π) orbital enhances the coupling ofthe orbital angular momentums with the electron spin, such that theT₁→S₀ transition would have a large First-order spin-orbit couplingterm, resulting in a drastic decrease of radiative lifetime and hence apossibility of increasing emission Q.Y. For probing such possibility,this group have prepared two isomeric, blue-emitting heterolepticiridium (III) complexes, namely complexes (dfppy)Ir(fppz)₂ (complex 1 inthe following) and (dfppy)Ir(fppz)₂ (complex 2 in the following). Thecontribution of MLCT character, which serves as a key factor inspin-orbit coupling enhancement, is calculated to be 27% and 17% for(dfppy)Ir(fppz)₂ (complex 1) and (dfppy)Ir(fppz)₂ (complex 2),respectively, according to the DFT calculation. As such, the respectivetheoretical analysis revealed an increase the d_(π) contribution in(dfppy)Ir(fppz)₂ (complex 1) versus that of complex 2, rendering alarger First-order spin-orbit coupling term and hence shorteningradiative lifetime as well as increasing the emission Q.Y., which areconsistent with the experimental observations.

Conversely, care has taken to avoid the enhanced radiationlessdeactivation pathways due to the purposed enlargement of the emissionband gap. One familiar deactivation pathway lies in the population tothe metal-centered dd excited states, which may cause the weakness ofthe metal-ligand bond, resulting in a shallow potential energy surface.In an extreme case, the shallow dd potential surface may intercept withother surfaces of states and greatly channel into the radiationlessdeactivation. This process, however, may be minor for the third-rowtransition metal elements due to their strong coordination strength thatfar pushes up the d_(π)* orbitals.

As for the third consideration, upon increasing the energy gap towardtrue-blue, it becomes facile for the lowest lying excited state, a stateperhaps consisting of both ππ* intraligand charge transfer (ILCT) andmetal-to-ligand charge transfer (MLCT) in character, to mix with athermally accessible ligand-to-ligand charge transfer (LLCT) character.Owing to its largely charge-separated character and hence partiallyforbidden transition probability (versus the ground state), mixing withthe LLCT excited state may eventually increase the radiative lifetime,hence reduce the corresponding Q.Y. if similar deactivation mechanismsare operative. Theoretically, the participation of LLCT excited statescan be suppressed by employing the facial arranged homoleptic complexes,for which the excitation is equally spread among the degenerate statesof multiple chromophores. The delocalization of the electron densitywould not only stabilize its molecular framework but also reduce theradiationless deactivation simply due to the resulting steeper potentialenergy surfaces. Moreover, for the unsymmetrical meridional isomer, thethree chelate ligands are located at the distinctive environment, thenon-degenerated nature of these chelate molecular orbitals would thenfacilitate the LLCT character and giving the poor emission Q.Y. at roomtemperature. Such a hypothesis was confirmed by a recent investigationon the photophysical behavior of the related homoleptic complexmer-[Ir(fppz)₃] (complex 3 in the above), for which an unprecedenteddual phosphorescence, i.e. a blue (P₁) and a green (P₂) bands derivingfrom the ILCT and LLCT excited states, are observed at room temperature.It is notable that the ILCT and LLCT excited states of mer-[Ir(fppz)₃]are nearly orthogonal to each other and possessing mainly the ligand ππ*character together with a small extent (˜10%) and an enhanced (20%) MLCTcharacter, respectively. Thus, the ILCT to LLCT energy transfer, whichtakes place at room temperature with small barrier possibly due tocertain large-amplitude motions, would also induce the rapidly quenchingof the higher energy, blue phosphorescence.

SUMMARY OF THE INVENTION

The present invention provides the phosphorescent metal complexes withone or two non-conjugated cyclometalated ligands, synthetic method ofpreparing the same and phosphorescent organic light emitting diodethereof for blocking the occurrence of unwanted LLCT processes andpossibly, giving an enhanced emission quantum yield more particularly inthe much needed true-blue region.

The present invention provides the phosphorescent metal complexes withone or two non-conjugated cyclometalated ligands, synthetic method ofpreparing the same and phosphorescent organic light emitting diodethereof for enhancing the quantum efficiency, synthetic yield of theiridium complexes and the luminous efficiency of phosphorescent OLEDs.

In the present invention, the molecular design of phosphorescent metalcomplexes comprises that, for the tris-chelated transition metalcomplexes, if one or two exceedingly large energy-gap cyclometalatedligands were incorporated into the coordination sphere with a transitionmetal, the subsequent radiative decay from the excited states will beconfined to the other one or two ligated chromophores that possess aslightly lowered energy gap (such as the gap for blue, green or redemission) due to the effective blocking of the ligand-to-ligand energytransfer process. Thus, this molecular design would suppress theunwanted LLCT processes, giving an enhanced emission quantum yield moreparticularly in the visible spectral region.

In the present invention, with the assistance of this basic designingprinciple and the incorporation of the chelating chromophores with arelatively lowered energy gap as well as the required rigid π-framework,the multicolor phosphorescent OLEDs doped with the metal complexes withefficient phosphorescent emission ranging from red, green and eventrue-blue can be successfully fabricated.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the present invention include (but not limitedto) the following items:

-   -   1. A phosphorescent tris-chelated transition metal complex        comprising i) two identical non-conjugated cyclometalated        ligands being incorporated into a coordination sphere thereof        with a transition metal, and one ligated chromophore being        incorporated into the coordination sphere; or ii) one        non-conjugated cyclometalated ligand forming a coordination        sphere thereof with a transition metal, and two ligated        chromophores being incorporated into the coordination sphere,        wherein the transition metal is iridium, platinum, osmium or        ruthenium, and the ligated chromophore possesses a relatively        lower energy gap in comparison with that of the non-conjugated        cyclometalated ligand, the latter afforded an effective barrier        for inhibiting the ligand-to-ligand charge transfer process, so        that a subsequent radiative decay from an excited state of these        transition metal complexes will be confined to the ligated        chromophore.    -   2. The complex of Item 1, wherein the energy gap of the ligated        chromophore is for blue, green or red emission.    -   3. The complex of Item 1, wherein the metal is iridium.    -   4. The complex of Item 3, wherein the complex is represented by        the following formulas Ia, Ib and their stereo isomers:

wherein the non-conjugated cyclometalated ligands are represented by Cand N linked with an arch, and has a formula of Ar₁—C(R₁R₂)—Ar₂, whereinAr₁ is aromatic ring, Ar₂ is N-heterocyclic ring, R₁ and R₂independently are H or methyl, wherein C in the formulas Ia and Ib is acarbon atom contained in Ar₁ and N in the formulas Ia and Ib is anitrogen atom contained in Ar₂; the ligated chromophore is presented bythe L and X linked with an arch, and has formula of Ar₃—Ar₄, wherein Ar₃and Ar₄ independently are an aromatic ring or N-heterocyclic ring, orAr₃—Ar₄ together are

wherein L is N or O, and X is C, N or O.

-   -   5. The complex of Item 3, wherein the complex is represented by        the following formulas IIa, IIb and their stereo isomers:

wherein the non-conjugated cyclometalated ligands are represented by Pand C linked with an arch, and has a formula of Ar₅—C(R₁R₂)—P(Ar₆Ar₇),wherein Ar₅, Ar₆ and Ar₇ independently are an identical aromatic ring ordifferent aromatic rings, R₁ and R₂ independently are H or methyl,wherein C in the formulas IIa and IIb is a carbon atom contained in Ar₅;the ligated chromophore is presented by the L and X linked with an arch,and has formula of Ar₃—Ar₄, wherein Ar₃ and Ar₄ independently are anaromatic ring or N-heterocyclic ring, or Ar₃—Ar₄ together are

wherein L is N or O, and X is C, N or O.

-   -   6. The complex of Item 4, wherein the non-conjugated        cyclometalated ligands are

wherein n is an integer of 1-3.

-   -   7. The complex of Item 6, wherein positions of F and        C_(n)F_(2n+1) groups on phenyl rings of the non-conjugated        cyclometalated ligands are varied, and n is 1.    -   8. The complex of Item 7, wherein F and C_(n)F_(2n+1) groups on        phenyl rings of the non-conjugated cyclometalated ligands are        independently replaced by CN group.    -   9. The complex of Item 5, wherein the non-conjugated        cyclometalated ligands are

wherein Ph is phenyl, and n is an integer of 1-3.

-   -   10. The complex of Item 9, wherein positions of F and        C_(n)F_(2n+1) groups on phenyl rings of the non-conjugated        cyclometalated ligands are varied, and n is 1.    -   11. The complex of Item 10, wherein F and C_(n)F_(2n+1) groups        on phenyl rings of the non-conjugated cyclometalated ligands are        independently replaced by CN group.    -   12. The complex of Item 4, wherein the ligated chromophores are

wherein Ph is phenyl.

-   -   13. The complex of Item 5, wherein the ligated chromophores are

wherein Ph is phenyl.

-   -   14. The complex of Item 3, wherein the complex is represented by        the following formulas IIIa, IIIb and their stereo isomers:

wherein the non-conjugated cyclometalated ligands are represented by Cand C linked with an arch, and has a formula of Ar₈—C(R₁R₂)—Ar₉, whereinAr₈ is aromatic ring, Ar₉ is N-heterocyclic carbene, R₁ and R₂independently are H or methyl, wherein C in the formulas IIIa and IIIbis a carbon atom contained in Ar₈ and Ar₉; the ligated chromophore ispresented by the L and X linked with an arch, and has formula ofAr₃—Ar₄, wherein Ar₃ and Ar₄ independently are an aromatic ring orN-heterocyclic ring, or Ar₃—Ar₄ together are

wherein L is N or O, and X is C, N or O.

-   -   15. The complex of Item 14, wherein the non-conjugated        cyclometalated ligands are

wherein n is an integer of 1-3.

-   -   16. The complex of Item 15, wherein positions of F and        C_(n)F_(2n+1) groups on phenyl rings of the two identical        non-conjugated cyclometalated ligands are varied, and n is 1.    -   17. The complex of Item 16, wherein F and C_(n)F_(2n+1) groups        on phenyl rings of the non-conjugated cyclometalated ligands are        independently replaced by CN group.    -   18. The complex of Item 14, wherein the ligated chromophores are

wherein Ph is phenyl.

The present invention also provides a phosphorescent organic lightemitting diode comprising the phosphorescent tris-chelated metal complexas defined in any one of Items 1 to 15 as an emitting or emitter dopantmaterial.

In one of the preferred embodiments of the present invention, thecyclometalated N-heterocyclic donors with an aliphatic spacer located atthe ligand center would serve as some much better candidates inconstructing such molecular design. The non-conjugated nature of thesespacer will interrupt the π-conjugation of the chelating ligands, whichthen lowers the relative energy of the ligand-centered π-orbitals anddestabilizing the respective π*-orbitals. With the assistance of thisbasic designing principle and the incorporation of the third chelatingchromophores with a rigid and slightly lower-energy π-framework, metalcomplexes with efficient phosphorescent emission ranging from red, greenand even true-blue can be successfully prepared.

The present invention will be better understood through the followingexamples, where are for illustrative only and not for limiting the scopeof the present invention.

PREPARATION EXAMPLES 1-4 Synthesis of Non-Conjugated ĈN Ligand

PREPARATION EXAMPLE 1 2,4-difluorobenzyl-N-pyrazole (1)

To a suspension of NaH (1.31 g, 54.8 mmol) in THF (25 mL) at 0° C. wasadded pyrazole (3.42 g, 50.2 mmol) under N₂. The mixture was stirreduntil the evolution of hydrogen had finished. A solution of2,4-difluorobenylbromide (6.0 mL, 45.7 mmol) in dry THF (10 mL) wasadded dropwise. The reaction mixture was stirred at room temperature for12 h. Resulting salt was then removed by filtration. Pure product wasobtained after column chromatography using ethyl acetate as eluent,giving 7.26 g of light yellow liquid (38.8 mmol, 84%).

Spectral data of 1. ¹H NMR (400 MHz, CDCl₃, 294K): δ 7.52 (d, J=2.0 Hz,1H, CH), 7.42 (d, J=2.0 Hz, 1H, CH), 7.15˜7.10 (m, 1H, CH), 6.85˜6.79(m, 2H, CH), 6.26 (t, J=2.0 Hz, 1H, CH), 5.30 (s, 2H, CH₂).

PREPARATION EXAMPLE 2 3-trifluoromethylbenzyl-N-pyrazole (2)

Ligand 2 was obtained in 90% by the similar procedure described forligand 1 in Preparation Example 1.

Spectral data of 2. ¹H NMR (300 MHz, CDCl₃, 294 K): δ 7.58˜7.55 (m, 4H,CH), 7.41 (d, J=2.2 Hz, 1H, CH), 7.25 (d, J=8.6 Hz, 1H, CH), 6.30 (t,J=2.2 Hz, 1H, CH), 5.37 (s, 2H, CH₂).

PREPARATION EXAMPLE 3 2,5-difluorobenzyl-N-pyrazole (3)

Ligand 3 was obtained in 94% by the similar procedure described forligand 1 in Preparation Example 1.

Spectral data of 3. ¹H NMR (300 MHz, CDCl₃, 294K): δ 7.54 (d, J=1.7 Hz,1H, CH), 7.45 (d, J=1.7 Hz, 1H, CH), 7.05˜6.91 (m, 2H, CH), 6.76˜6.70(m, 1H, CH), 6.29 (t, J=1.7 Hz, 1H, CH), 5.34 (s, 2H, CH₂).

PREPARATION EXAMPLE 4 2-trifluoromethyl-5-fluorobenzyl-N-pyrazole (4)

Ligand 4 was obtained in 90% by the similar procedure described orligand 1 in Preparation Example 1.

Spectral data of 4. ¹H NMR (300 MHz, CDCl₃, 294 K): δ 7.67 (m, 2H, CH),7.44 (d, J=2.0 Hz, 1H, CH), 7.03 (t, J=7.8 Hz, 1H, CH), 6.50 (d, J=9.5Hz, 1H, CH),6.35 (t, J=2.0 Hz, 1H, CH), 5.53 (s, 2H, CH₂).

EXAMPLES 1a-4b Synthesis of Ir(ĈN)₂LX

Ir(2,4-dfb-pz)₂LX Series (1a-1j)

Synthetic method of preparing this series of iridium complexes[Ir(2,4-dfb-pz)₂(L̂X)] were much better executed by heating of a 2:1mixture of (2,4-dfp-pz)H and IrCl₃.3H₂O in methoxyethanol (140° C. 24hr), followed by treatment with 1.1 equiv. of chelating anions (L̂X)H inpresence of proton scavenger Na₂CO₃ (RT, 8 hr), for which severalrepresentative examples for the L̂X ligands are shown in Chart of FIG. 4.The isolated products are separated by column chromatography on silicagel eluting with a mixture of ethyl acetate and hexane (1:1). It isbelieved that the reaction proceeded via the formation of anintermediate with proposed formula [Ir(2,4-dfb-pz)₂(μ-Cl)]₂. After then,addition of the chelating anion (L̂X) would induce the rapid cleavage ofdimer, giving the monometallic products with formula[Ir(2,4-dfb-pz)₂(L̂X)]. Moreover, if the reactions with L̂X ligand wereconducted in refluxing methoxyethanol, a reduction of product yield wasnoted, which showed the intricate nature of such substitution reaction.

EXAMPLE 1a Ir(2,4-dfb-pz)₂(fppz) (1a)

A mixture of 2,4-difluorobenzyl-N-pyrazole (0.23 g, 1.18 mmol) andIrCl₃.3H₂O (0.20 g, 0.57 mmol) in 2-methoxyethanol (5 mL) was reflux for24 hours under nitrogen. After cooling the solution to room temperature,3-trifluoromethyl-5-(2-pyridyl) pyrazole (0.12 g, 0.567 mmol) and Na₂CO₃(60 mg, 0.567 mmol) was added and the mixture was stir at RT for further12 hours. Excess of water was added and the resulting precipitate wascollected by filtration and washed with MeOH. Further purification wasconducted by silica gel column chromatography using CH₂Cl₂ as eluent,giving 0.22 g of pearl solid (0.278 mmol, 49%).

Spectral data of 1a: MS (FAB), m/z 792, (M+1)⁺. ¹H NMR (500 MHz,d-acetone, 194 K): δ 8.80 (d, J=5.5 Hz, 1H, CH), 8.32 (d, J=2.0 Hz, 1H,CH), 8.24 (d, J=2.0 Hz, 1H, CH), 8.08 (d, J=3.5 Hz, 2H, CH), 7.50 (m,1H, CH), 7.37 (d, J=2.0 Hz, 1H, CH), 7.26 (s, 1H, CH), 7.00 (d, J=2.0Hz, 1H, CH), 6.69 (td, J=10.0 Hz, 2.0 Hz, 1H, CH), 6.56 (td, J=10.0 Hz,2.0 Hz, 1H, CH), 6.43 (t, J=2.0 Hz, 1H, CH), 6.36 (t, J=2.0 Hz, 1H, CH),6.02 (d, J=14.5 Hz, 1H, CH₂), 5.97 (d, J=16.0 Hz, 1H, CH₂), 5.86 (d,J=14.5 Hz, 1H, CH₂), 5.05 (dd, J=10.0 Hz, 2.0 Hz, 1H, CH), 5.00 (d,J=16.0 Hz, 1H, CH₂), 4.72 (dd, J=10.0 Hz, 2.0 Hz, 1H, CH). ¹⁹F NMR (470MHz, d-acetone, 194 K): δ −59.70 (s, 3F, CF₃), −115.09 (s, 1F, CF),−115.77 (s, 1F, CF), −117.73 (s, 1F, CF), −119.71 (s, 1F, CF). Anal.Calcd. For C₂₉H₁₉F₇IrN₇: N, 12.40; C, 44.05; H, 2.42. Found: N, 11.63;C, 43.64; H, 2.69.

EXAMPLE 1b Ir(2,4-dfb-pz)₂(fptz) (1b)

A mixture of 2,4-difluorobenzyl-N-trazole (0.35 g, 1.79 mmol) andIrCl₃.3H₂O (0.30 g, 0.851 mmol) in 2-methoxyethanol (5 mL) was refluxfor 24 hours under nitrogen. After cooling the solution to roomtemperature, 3-trifluoromethyl-5-(2-pyridyl) triazole (182 mg, 0.851mmol) and Na₂CO₃ (90 mg, 0.851 mmol) was added and the mixture was stirat RT for further 12 hours. Excess of water was added and the resultingprecipitate was collected by filtration and washed with MeOH and ether.Further purification was conducted by recrystallization usingacetone/hexane, giving 0.40 g of colorless solid (0.501 mmol, 59%).

Spectral data of 1b: MS (FAB), m/z 793, (M+1)⁺. ¹H NMR (400 MHz,d-acetone, 294 K): δ 8.78 (br, 1H, CH), 8.19˜8.15 (m, 3H, CH), 8.11 (d,J=2.8 Hz, 1H, CH), 8.65 (m, 1H, CH), 7.19 (s, 1H, CH), 6.98 (s, 1H, CH),6.57 (td, J=9.6 Hz, 2.4 Hz, 1H, CH), 6.45 (td, J=9.6 Hz, 2.4 Hz, 1H,CH), 6.32 (t, J=2.4 Hz, 1H, CH), 6.30 (t, J=2.4 Hz, 1H, CH), 5.79 (d,J=14.8 Hz, 1H, CH₂), 5.61 (br, 2H, CH+CH₂), 5.36 (br, 2H, CH+CH₂), 5.14(d, J=15.2 Hz, 1H, CH₂). Anal. Calcd. For C₂₈H₁₈F₇IrN₈: N, 14.15; C,42.48; H, 2.29. Found: N, 13.53; C, 42.28; H, 2.62.

EXAMPLE 1c Ir(2,4-dfb-pz)₂(pyN4) (1c)

Compound 1c was obtained in 42% by the similar procedure described forthe complex 1b in Example 1b.

Spectral data of 1c: MS (FAB), m/z 726, (M+1)⁺. ¹H NMR (300 MHz,d-acetone, 294 K): δ 8.81 (br, 1H, CH), 8.34 (d, J=7.9 Hz, 1H, CH), 8.23(td, J=7.9 Hz, 1.5 Hz, 1H, CH), 8.18 (d, J=2.4 Hz, 1H, CH), 8.12 (d,J=2.4 Hz, 1H, CH), 7.69 (ddd, J=7.9 Hz, 5.7 Hz, 1.2 Hz, 1H, CH), 7.17(s, 1H, CH), 6.85 (s, 1H, CH), 6.60 (ddd, J=2.4 Hz, 1H, CH), 6.50 (ddd,J=14.8 Hz, 1H, CH₂), 6.33 (t, J=2.5 Hz, 1H, CH), 6.29 (t, J=2.5 Hz, 1H,CH), 5.70 (m, 3H, CH+CH₂), 5.40 (br, 1H, CH), 5.16 (d, J=15.5 Hz, 2H,CH₂).

EXAMPLE 1d Ir(2,4-dfb-pz)₂(fpbpz) (1d)

Compound 1d was obtained in 32% by the similar procedure described forthe compound 1a in Example 1a. Purification was conducted by silica gelcolumn chromatography using EA/hexane (1:2) as eluent.

Spectral data of 1d: MS (FAB), m/z 848, (M+1)⁺. ¹H NMR (400 MHz,d-acetone, 294 K): δ 8.55 (d, J=5.0 Hz, 1H, CH), 8.13 (d, J=2.4 Hz, 1H,CH), 8.08˜8.05 (m, 2H, CH), 7.46 (dd, J=6.0 Hz, 2.4 Hz, 1H, CH), 7.19(s, 1H, CH), 7.16 (s, 1H, CH), 7.03 (s, 1H, CH), 6.53 (td, J=9.6 Hz, 2.4Hz, 1H, CH), 6.39 (td, J=9.6 Hz, 2.4 Hz, 1H, CH), 6.31 (t, J=2.4 Hz, 1H,CH), 6.27 (t, J=2.4 Hz, 1H, CH), 6.00 (d, J=14.8 Hz, 1H, CH₂), 5.67 (br,3H, CH+CH₂), 5.34 (br, 1H, CH), 5.08 (d,J=15.6 Hz, 1H, CH₂), 1.37 (s,9H, CH₃). Anal. Calcd. For C₃₃H₂₇F₇IrN₇: N, 11.58; C, 46.80; H, 3.21.Found: N,10.44; C, 47.72; H, 3.73.

EXAMPLE 1e Ir(2,4-dfb-pz)₂(fpbtz) (1e)

Compound 1e was obtained in 40% by the similar procedure described forthe compound 1a in Example 1a. Purification was conducted by silica gelcolumn chromatography using EA/hexane (2:3) as eluent.

Spectral data of 1e: MS (FAB), m/z 849, (M+1)⁺. ¹H NMR (400 MHz,d-acetone, 294 K): δ 8.65 (br, 1H, CH), 8.16˜8.10 (m, 3H, CH), 7.68 (dd,J=5.6 Hz, 1.6 Hz, 1H, CH), 7.16 (s, 1H, CH), 6.97 (s, 1H, CH), 6.57(ddd, J=10.2 Hz, 8.6 Hz, 2.4 Hz, 1H, CH), 6.44 (ddd, J=10.2 Hz, 8.6 Hz,2.4 Hz, 1H, CH), 6.32 (t, J=2.4 Hz, 1H, CH), 6.29 (t, J=2.4 Hz, 1H, CH),5.79 (d, J=14.0 Hz, 1H, CH₂), 5.62 (br, 3H, CH+CH₂), 5.37 (br, 1H, CH),5.12 (d, J=15.6 Hz, 1H, CH₂),1.41 (s, 9H, CH₃). Anal. Calcd. ForC₃₂H₂₆F₇IrN₈: N, 13.22; C, 45.33; H, 3.09. Found: N, 12.90; C, 45.37; H,3.41.

EXAMPLE 1f Ir(2,4-dfb-pz)₂(ppbtz) (1f)

Compound 1f was obtained in 40% by the similar procedure described forthe parent compound 1a in Example 1a. Purification was conducted bysilica gel column chromatography using CH₂Cl₂ as eluent.

Spectral data of 1f: MS (FAB), m/z 857, (M+1)⁺. ¹H NMR (400 MHz,d-acetone, 294 K): δ 8.62 (d, J=5.4 Hz, 1H, CH), 8.18˜8.15 (m, 3H, CH),8.13 (d, J=2.4 Hz, 1H, CH), 8.08 (d, J=2.4 Hz, 1H, CH), 7.58 (dd, J=6.0Hz, 2.4 Hz, 1H, CH), 7.40˜7.27 (m, 2H, CH), 7.29 (td, J=7.6 Hz, 2.0 Hz,1H, CH), 7.19˜7.16 (m, 2H, CH), 6.55 (ddd, J=10.4 Hz, 9.2 Hz, 2.4 Hz,1H, CH), 6.44 (ddd, J=10.4 Hz, 9.2 Hz, 2.4 Hz, 1H, CH), 6.30 (t, J=2.4Hz, 1H, CH), 6.25 (t, J=2.4 Hz, 1H, CH), 6.12˜5.61 (br, 2H, CH+CH₂),5.38˜5.07 (br, 4H, CH), 1.40 (s, 9H, CH₃). Anal. Calcd. forC₃₇H₃₁F₄IrN₈.CH₂Cl₂: N, 11.91; C, 48.51; H, 3.54. Found: N, 12.08; C,48.60; H, 3.75.

EXAMPLE 1g Ir(2,4-dfb-pz)₂(bpbtz) (1g)

Compound 1g was obtained in 63% by the similar procedure described forthe parent compound 1a in Example 1a. Purification was conducted byflash column chromatography using CH₂Cl₂ as eluent.

Spectral data of 1g: MS (FAB), m/z 837, (M+1)⁺. ¹H NMR (400 MHz,d-acetone, 294 K): δ 8.60 (d, J=6.0 Hz, 1H, CH), 8.11 (d, J=2.4 Hz, 1H,CH), 8.06 (d, J=2.4 Hz, 1H, CH), 7.99 (s, 1H, CH), 7.52 (dd, J=6.0 Hz,2.4 Hz, 1H, CH), 7.18 (s, 1H, CH), 7.12 (br, 1H, CH), 6.52 (ddd, J=10.8Hz, 8.8 Hz, 2.4 Hz, 1H, CH), 6.39 (ddd, J=10.4 Hz, 9.2 Hz, 2.4 Hz, 1H,CH), 6.30 (t, J=2.4 Hz, 1H, CH), 6.25 (t, J=2.4 Hz, 1H, CH), 6.12 (d,J=15.6 Hz, 1H, CH₂), δ5.26 (br, 3H, CH+CH₂), 5.01˜4.88 (m, 2H, CH+CH₂),1.37 (s,9H, CH₃), 1.35 (s,9H, CH₃). Anal. Calcd. for C₃₅H₃₅F₄IrN₈.0.5CH₂Cl₂: N, 12.76; C, 48.54; H, 4.13. Found: N, 12.55; C, 48.16; H,4.25.

EXAMPLE 1h Ir(2,4-dfb-pz)₂(fpy) (1h)

Compound 1h was obtained in 24% by the similar procedure described forthe parent compound 1a in Example 1a. Purification was conducted bycolumn chromatography using CH₂Cl₂/hexane (1:2) as eluent.

Spectral data of 1h: MS (FAB), m/z 858, (M)⁺. ¹H NMR (400 MHz,d-acetone, 294 K): δ 8.25 (d, J=8.0 Hz, 1H, CH), 8.12 (dd, J=9.2 Hz, 2.4Hz, 2H, CH), 8.01 (ddd, J=8.8 Hz, 8.0 Hz, 1.2 Hz, 1H, CH), 7.85 (d,J=5.6 Hz, 1H, CH), 7.13˜7.10 (m, 2H, CH), 6.87 (s, 1H, CH), 6.71 (d,J=2.4 Hz, 1H, CH), 6.63 (ddd, J=12.8 Hz, 9.2 Hz, 2.8 Hz, 1H, CH),6.47˜6.40 (m, 2H, CH), 6.37 (t, J=2.4 Hz, 1H, CH), 6.34 (t, J=2.4 Hz,1H, CH), 6.28 (d, J=10.0 Hz, 1H, CH), 5.56 (d, J=15.2 Hz, 1H, CH₂), 5.52(d, J=15.2 Hz, 1H, CH₂), 4.72 (d, J=15.2 Hz, 1H, CH₂), 4.69 (d, J=15.2Hz, 1H, CH₂). Anal. Calcd. For C₃₁H₁₉F₁₀IrN₆: N, 9.80; C, 43.41; H,2.23. Found: N, 9.81; C, 43.44; H, 2.58.

EXAMPLE 1i Ir(2,4-dfb-pz)₂(acac) (1i)

Compound 1i was obtained in 72% by the similar procedure described forthe parent compound 1a in Example 1a. Purification was conducted bycolumn chromatography using EA/hexane (1:1) as eluent andrecrystallization using CH₂Cl₂ and hexane.

Spectral data of 1i: MS (FAB), m/z 678, (M)⁺. ¹H NMR (400 MHz,d-acetone, 294 K): δ 8.14 (d, J=2.0 Hz, 2H, CH), 7.41 (br, 2H, CH), 6.49(t, J=2.0 Hz, 2H, CH), 6.34 (td, J=8.0 Hz, 1.6 Hz, 2H, CH), 5.59˜5.12(m, 7H, CH+CH₂), 1.84 (s, 6H, CH₃). Anal. Calcd. ForC₂₅H₂₁F₄IrN₄O₂.CH₂Cl₂: N, 7.35; C, 40.95; H, 3.04. Found: N, 7.47; C,41.14; H, 3.37.

EXAMPLE 1j Ir(2,4-dfb-pz)₂(pic) (1j)

Compound 1j was obtained in 30% by the similar procedure described forthe parent compound 1a in Example 1a. Purification was conducted bycolumn chromatography using EA/hexane (2:1) as eluent andrecrystallization using CH₂Cl₂ and MeOH.

Spectral data of 1j: MS (FAB), m/z 702, (M+1)⁺. ¹H NMR (400 MHz, CDCl₃,294 K): δ 8.35 (br, 2H, CH), 7.96 (t, J=8.0 Hz, 1H, CH), 7.62 (d, J=2.4Hz, 1H, CH), 7.57 (d, J=2.4 Hz, 1H, CH), 7.50 (t, J=6.4 Hz, 1H, CH),7.40 (d, J=2.4 Hz, 1H, CH), 6.86 (d, J=2.4 Hz, 1H, CH), 6.43 (td, J=9.6Hz, 2.4 Hz, 1H, CH), 6.31 (td, J=9.6 Hz, 2.4 Hz, 1H, CH), 6.27 (t, J=2.4Hz, 1H, CH), 6.19 (t, J=2.4 Hz, 1H, CH), 5.62˜4.97 (br, 6H, CH+CH₂).Anal. Calcd. For C₂₆H₁₈F₄IrN₅O₂: N, 10.00; C, 44.57; H, 2.59. Found: N,9.82; C, 45.15; H, 2.96.

4.1 Ir(4-CF₃b-pz)₂LX Series (2a-2b) EXAMPLE 2a Ir(4-tfmb-pz)₂(fppz) (2a)

A mixture of 4-trifluoromethylbenzyl-N-pyrazole (0.20 g, 0.89 mmol) andIrCl₃.3H₂O (0.15 g, 0.43 mmol) in 2-methoxyethanol (5 mL) was reflux for24 hours under nitrogen. After cooling the solution to room temperature,3-trifluoromethyl-5-(2-pyridyl) pyrazole (91 mg, 0.43 mmol) and Na₂CO₃(0.23 g, 2.17 mmol) was added and the mixture was stir at RT for further12 hours. Excess of water was added and the resulting precipitate wascollected by filtration. Further purification was conducted by flashcolumn chromatography using CH₂Cl₂ as eluent, giving 127 mg of yellowpowder (0.149 mmol, 35%).

Spectral data of 2a: MS (FAB), m/z 856, (M+1)⁺. ¹H NMR (400 MHz,d-acetone, 294 K): δ 8.57 (br, 1H, CH), 8.04˜7.98 (m, 3H, CH), 7.96 (d,J=2.4 Hz, 1H, CH), 7.40 (td, J=5.6 Hz, 2.4 Hz, 1H, CH), 7.29 (d, J=8.0Hz, 1H, CH), 7.18˜7.15 (m, 3H, CH), 7.11 (s, 1H, CH), 7.03˜6.98 (m, 2H,CH), 6.28 (t, J=2.4 Hz, 1H, CH), 6.23 (t, J=2.4 Hz, 1H, CH), 6.08˜5.81(br, 3H, CH+CH₂), 5.48˜5.29 (m, 3H, CH+CH₂). Anal. Calcd ForC₃₁H₂₁F₉IrN₇: N, 11.47; C, 43.56; H, 2.48. Found: N, 11.02; C, 44.15; H,2.99.

EXAMPLE 2b Ir(4-tfmb-pz)₂(fptz) (2b)

Compound 2b was obtained in 31 % by the similar procedure described forthe parent compound 2a in Example 2a. Purification was conducted byflash column chromatography using CH₂Cl₂ as eluent.

Spectral data of 2b: MS (FAB), m/z 857, (M+1)⁺. ¹H NMR (400 MHz,d-acetone, 294 K): δ 8.70 (br, 1H, CH), 8.20˜8.14 (m, 2H, CH), 8.06 (d,J=2.4 Hz, 1H, CH), 7.99 (d, J=2.4 Hz, 1H, CH), 7.63 (td, J=6.4 Hz, 2.4Hz, 1H, CH), 7.33 (d, J=8.0 Hz, 1H, CH), 7.23˜7.18 (m, 3H, CH), 7.06 (d,J=6.4 Hz, 1H, CH), 6.99 (d, J=2.4 Hz, 1H, CH), 6.30 (t, J=2.4 Hz, 1H,CH), 6.26 (d, J=2.4 Hz, 1H, CH₂), 6.06˜5.75 (br, 3H, CH+CH₂), 5.53˜5.37(m, 3H, CH+CH₂). Anal. Calcd. For C₃₀H₂₀F₉IrN₈: N, 13.09; C, 42.11; H,2.36. Found: N, 12..84; C, 42.10; H, 2.66.

Ir(2,5-dfb-pz)₂LX Series (3a-3b) EXAMPLE 3a Ir(2,5-dfb-pz)₂(fppZ) (3a)

Compound 3a was obtained in 28% by the similar procedure described forthe parent compound 1a in Example 1a. Purification was conducted bycolumn chromatography using CH₂Cl₂ as eluent.

Spectral data of 3a: MS (FAB), m/z 792, (M+1)⁺ Anal. Calcd. ForC₂₉H₁₉F₇IrN₇.CH₃COCH₃: N, 11.55; C, 45.28; H, 2.97. Found: N, 11.11; C,45.51; H, 3.28.

EXAMPLE 3b Ir(2,5-dfb-pz)₂(fptz) (3b)

Compound 3b was obtained in 30% by the similar procedure described forthe parent compound 1a in Example 1a. Purification was conducted bycolumn chromatography using CH₂Cl₂ as eluent and recrystallization usingCH₂Cl₂ and hexane.

Spectral data of 3b: MS (FAB), m/z 793, (M+1)⁺. ¹⁹F NMR (470 MHz,d-acetone, 294 K): δ−63.31 (s, 3F, CF₃, 3b′), −63.42 (s, 3F, CF₃, 3b),−104.73 (s, 1F, CF, 3b′), −105.85 (s, 1F, CF, 3b), −106.72 (s, 1F, CF,3b′), −109.91 (s, 1F, CF, 3b), −124.88 (s, 1F, CF, 3b′), −125.53 (s, 1F,CF, 3b), −126.10 (s, 1F, CF, 3b′), −126.64 (s, 1F, CF, 3b). Anal. Calcd.For C₂₈H₁₈F₇IrN₈: N, 14.15; C, 42.48; H, 2.29. Found: N, 13.84; C,42.26; H, 2.70.

Ir(tfmfb-pz)₂LX Series (4a-4b) EXAMPLE 4a Ir(tfmfb-pz)₂(fppz) (4a)

A mixture of 2-trifluoromethyl-5-fluorobenzyl-N-pyrazole (75 mg, 0.31mmol) and IrCl₃.3H₂O (54 mg, 0.15 mmol) in 2-methoxyethanol (4 mL) wasreflux for 2 days under nitrogen. After cooling the solution to roomtemperature, 3-trifluoromethyl-5-(2-pyridyl)pyrazole (33 mg, 0.15 mmol)and Na₂CO₃ (81 mg, 0.77 mmol) was added and the mixture was stir at RTfor further 12 hours. Excess of water was added and the resultingprecipitate was collected by filtration. Further purification wasconducted by column chromatography using CH₂Cl₂/hexane (1:1) as eluent,giving 42 mg of white powder (0.05 mmol, 31%).

Spectral data of 4a: MS (FAB), m/z 892, (M+1)⁺. ¹⁹F NMR (470 MHz,d-acetone, 294 K): δ −57.14 (s, 6F, CF₃, 4a), −57.40 (s, 3F, CF₃, 4a′),−57.59 (s, 3F, CF₃, 4a′), −60.24 (s, 3F, CF₃, 4a′), −60.59 (s, 3F, CF₃,4a), —88.20 (s, 1F, CF, 4a′), −91.21 (s, 1F, CF, 4a), −91.54 (s, 1F, CF,4a′), −95.02 (s, 1F, CF, 4a). Anal. Calcd. For C₃₁H₁₉F₁₁IrN₇.CH₂Cl₂: N,10.05; C, 39.39; H, 2.17. Found: N, 10.02; C, 39.67; H, 2.55.

EXAMPLE 4b Ir(tfmfb-pz)₂(fptz) (4b)

Compound 4b was obtained in 28% by the similar procedure described forthe parent compound 4a in Example 4a. Purification was conducted bycolumn chromatography using CH₂Cl₂/hexane (1:3) as eluent andrecrystallization using CH₂Cl₂/hexane double layer system.

Spectral data of 4b: MS (FAB), m/z 893, (M+1)⁺. ¹⁹F NMR (470 MHz,d-acetone, 294 K): δ −57.21 (s, 6F, CF₃, 4b), −57.54 (s, 3F, CF₃, 4b′),−57.67 (s, 3F, CF₃, 4b′), −63.70 (s, 3F, CF₃, 4b′), −64.03 (s, 3F, CF₃,4b), −88.72 (s, 1F, CF, 4b′), −91.34 (s, 1F, CF, 4b), −91.85 (s, 1F, CF,4b′), −94.87 (s, 1F, CF, 4b). Anal. Calcd. For C₃₀H₁₈F₁₁IrN₈.CH₂Cl₂: N,11.47; C, 38.12; H, 2.06. Found: N, 11.45; C, 38.31; H, 2.37.

EXAMPLE 5a-5b Synthesis of Ir(ĈP)₂LX

EXAMPLE 5a Ir(bdpp)₂(fppz) (5a)

A 25 mL flask was charged with IrCl₃.3H₂O (210 mg, 0.6 mmol) andbenzyldiphenyl phosphine (331 mg, 1.2 mmol) then dry and degassed2-methoxyethanol (10 mL) was added as solvent. The reaction mixture washeated at 120° C. for 12 hour. After cooling to room temperature, fppzH(86 mg, 0.4 mmol) and Na₂CO₃ (636 mg, 6.0 mmol) were added into theflask, followed by stirring at RT for another 3 hour. The reaction wasquenched by addition of excess water which resulted in the pale yellowprecipitate. The precipitate was collected by the filtration and thenwashed with ice MeOH and diethyl ether. Purification by flash columnusing CH₂Cl₂ as eluent gave a chloride intermediate which could befurther purified by recrystallization in mixed CH₂Cl₂ and hexanesolution with 40% yield (240 mg, 0.24 mmol). After then, a mixture ofchloride intermediate (99 mg, 0.1 mmol), AgOTf (28 mg, 0.12 mmol) anddry 2-methoxyethanol (5 mL) was refluxed in the dark for 2 hour and thencooled to room temperature. After removal of the white precipitate byfiltration, the collected filtrate was added excess water. The resultingwhite precipitate could be collected by filtration, followed by washingwith ice methanol and diethyl ether. Purification was conducted by flashcolumn using CH₂Cl₂ as eluent and then recrystallization in mixedsolution of CH₂Cl₂ and hexane gave 5a as white powder with 37% yield (70mg, 0.037 mmol).

Spectral data of 5a: MS (FAB, 192Ir), 955 [M+]. ¹H NMR (500 MHz, CDCl₃,294K): δ 7.89 (d, J=8.0 Hz, 1H), 7.87 (d, J=8.0 Hz, 1H), 7.50 (d, J=6.5Hz, 1H), 7.43 (t, J=9.0 Hz, 2H), 7.33-7.25 (m, 3H), 7.21 (d, J=7.5 Hz,1H), 7.16-7.13 (m, 3H), 7.11-7.08 (m, 5H), 6.96 (t, J=7.5 Hz, 1H), 6.85(t, J=7.5 Hz, 1H), 6.82-6.79 (m, 3H), 6.77 (s, 1H), 6.72 (t, J=7.3 Hz,1H), 6.69-6.66 (m, 3H), 6.61 (t, J=8.8 Hz, 2H), 6.43 (t, J=6.8 Hz, 1H),6.32 (t, J=8.5 Hz, 2H), 6.18 (t, J=5.8 Hz, 1H), 4.05 (dd, J=15.0, 8.8Hz, 1H), 3.77 (dd, J=15.0, 8.8 Hz, 1H), 3.46 (dd, J=16.5, 9.7 Hz, 1H),2.17 (dd, J=16.5, 9.7 Hz, 1H). ¹⁹F {¹H} NMR (470 MHz, CDCl3, 294K): δ−60.27 (s, 3F).³¹P {¹H} NMR (202 MHz, CDCl₃, 294K): δ 6.29 (d, J=11.1Hz, 1P), 6.18 (d, J=11.1 Hz, 1P).

EXAMPLE 5b Ir(bdpp)₂(fpbpz) (5b)

The synthesis procedures of complex 5b is similar with that of 5a exceptthe fppzH was replaced by fpbpzH (168 mg, 0.6 mmol) and the yield of 5bis 32%.

Spectral data of 5b: MS (FAB, ¹⁹²Ir), 1012 [M+1⁺]. ¹H NMR (500 MHz,CDCl₃, 294K): δ 7.94 (d, J=8.0 Hz, 1H), 7.92 (d, J=8.0 Hz, 1H), 7.44 (t,J=8.8 Hz, 2H), 7.35 (dd, J=6.3, 2.8 Hz, 1H), 7.31-7.26 (m, 2H),7.20-7.07 (m, 8H), 6.95 (t, J=7.5 Hz, 2H), 6.86 (t, J=7.5 Hz, 1H),6.81-6.78 (m, 4H), 6.73 (t, J=7.5 Hz, 1H), 6.70-6.64 (m, 3H), 6.58 (t,J=8.5 Hz, 2H), 6.45 (t, J=6.0 Hz, 1H), 6.32 (t, J=8.5 Hz, 2H), 6.21 (t,J=6.0 Hz, 1H), 4.23 (dd, J=14.5, 8.8 Hz, 1H), 3.74 (dd, J=14.5, 8.8 Hz,1H), 3.44 (dd, J=16.5, 10.0 Hz, 1H), 2.09 (dd, J=16.5, 10.0 Hz, 1H),1.17 (s, 9H). ¹⁹F {¹H} NMR (470 MHz, CDCl3, 294K): δ −60.21 (s,3F).³¹P{¹H} NMR (202 MHz, CDCl₃, 294K): δ 6.38 (d, J=7.5 Hz, 1P), 6.18(d, J=7.5 Hz, 1P).

PREPARATION EXAMPLES 6-8 Synthesis of Non-Conjugated CAC Ligand Bromide

PREPARATION EXAMPLE 6 bmbH₂Br

1-methylbenzimidazol (0.322 g, 2.43 mmol) and benzyl bromide (0.417 g,2.43 mmol) were stirred in EtOAc (8 mL) at room temperature for 24 h.The precipitate was collected by filtration and dried in vacuum. Theproduct was obtained as white solid in 47% yield (0.344 g, 1.14 mmol).

Spectra data of bmbH₂Br: ¹H NMR (400 MHz, d₆-DMSO, 298 K): δ 9.84 (s,1H), 8.02 (d, 2H, J_(HH)=8.4 Hz), 7.94 (d, 2H, J_(HH)=8.4 Hz), 7.64˜7.70(m, 2H), 7.50 (d, 2H, J_(HH)=7.2 Hz), 7.42˜7.36 (m, 3H), 5.77 (s, 2H),4.09 (s, 3H).

PREPARATION EXAMPLE 7 dfbmbH₂Br

dfbmbH₂Br was obtained in 73% by the similar procedure described forbmbH₂Br.

Spectra data of dfbmbH₂Br: ¹H NMR (400 MHz, d₆-DMSO, 298 K): δ 9.83 (s,1H), 8.04˜7.99 (m, 2H), 7.77˜7.68 (m, 3H), 7.41˜7.36 (m, 1H), 7.18 (ddd,1H, J_(HF)=8.60, J_(HH)=8.4, 2.4 Hz), 5.82 (s, 2H, CH₂), 4.09 (s, 3H,Me).

PREPARATION EXAMPLE 8 fbmbH₂Br

fbmbH₂Br was obtained in 81% by the similar procedure described forbmbH₂Br.

Spectra data of fbmbH₂Br: ¹H NMR (400 MHz, d₆-DMSO, 298 K): δ 9.81 (s,1H), 8.02 (dd, 1H, J_(HH)=7.2, 1.6 Hz), 7.95 (dd, 1H, J_(HH)=7.2, 1.6Hz), 7.70˜7.63 (m, 2H), 7.60˜7.57 (m, 2H), 7.28˜7.23 (m, 2H), 5.75 (s,2H), 4.08 (s, 3H).

PREPARATION EXAMPLES 9-11 Synthesis of Non-Conjugated CAC Ligand

PREPARATION EXAMPLE 9 Bis(3-benzyl-1-methyl-benzimidazolin-2-ylidene)silver bromide (6)

A 50 mL round-bottom flask was charged with silver (I) oxide (80 mg,0.35 mmol), bmbH₂Br (70 mg, 0.323 mmol) and 20 mL of CH₂Cl₂. Thereaction mixture was stirred and refluxed overnight under nitrogen whileprotected from light with aluminum foil. The reaction mixture was cooledto ambient temperature. Flash column chromatography on celite usingCH₂Cl₂ as eluent was performed to remove the silver (I) salt. Acolorless solution was obtained and concentrated. The product wasobtained as white solid in 69% yield (50 mg, 0.079 mmol).

Spectra data of 6: MS (FAB): 553 (M⁺). ¹H NMR (400 MHz, d₆-DMSO, 298 K):δ 7.46˜7.33 (m, 8H), 7.71 (d, 2H, J_(HH)=8 Hz), 7.77 (d, 2H, J_(HH)=7.6Hz), 7.32˜7.25 (m, 6H), 5.71 (s, 4H), 4.05 (s, 6H).

PREPARATION EXAMPLE 10 Bis(3-(2,4-diflourobenzyl)-1-methylbenzimidazolin-2-ylidene) silver bromide (7)

Ligand 7 was obtained in 83% by the similar procedure described forligand 6.

Spectra data of 7: ¹H NMR (400 MHz, d₆-DMSO, 298 K): δ 7.76 (d, 2H,J_(HH)=7.2 Hz), 7.72 (d, 2H, J_(HH)=7.2 Hz), 7.48˜7.37 (m, 6H),7.31˜7.26 (m, 2H), 7.03 (ddd, 2H, J_(HH)=8.0, 2.4, J_(HF)=8.4 Hz), 5.71(s, 4H), 4.06 (s, 6H).

PREPARATION EXAMPLE 11 Bis(3-(4-diflourobenzyl)-1-methylbenzimidazolin-2-ylidene) silver bromide (8)

Ligand 8 was obtained in 84% by the similar procedure described forligand 6.

Spectra data of 8: ¹H NMR (400 MHz, d₆-DMSO, 298 K): δ 7.77 (d, 2H,J_(HH)=7.2 Hz), 7.72 (d, 2H, J_(HH)=7.2 Hz), 7.44˜7.40 (m, 8H),7.17˜7.13 (m, 4H), 5.70 (s, 4H), 4.05 (s, 6H).

EXAMPLE 6a-8b Synthesis of Ir(ĈC)₂LX

EXAMPLE 6a [Ir(bmb)₂(fptz)] (6a)

A xylene solution (20 mL) of IrCl₃(THT)₃ (70 mg, 0.125 mmol) and[(bmbH)₂Ag].Br (102 mg, 0.125 mmol) was heated at 130° C. for 12 h.After cooling to room temperature, bptzH (28.3 mg, 0.125 mmol) andNa₂CO₃ (0.132 g, 1.25 mmol) were added and this mixture was heated at130° C. for another 24 h. Solution was concentrated under reducedpressure. Flash column chromatography on celite using CH₂Cl₂ as theeluent was performed to remove the insoluble materials. After removingsolvent, the residue was purified by column chromatography eluting withCH₂Cl₂, and recrystallized from CH₂Cl₂/hexane to give yellow solid in12% yield (12 mg, 0.014 mmol).

Spectra data of compound 6a: MS (FAB), 848 (M+). ¹H NMR (400 MHz, CDCl₃,298 K): δ 9.54 (d, 1H, J_(HH)=6.4 Hz), 8.05 (d, 1H, J_(HH)=7.6 Hz), 7.73(t, 1H, J_(HH)=7.6 Hz), 7.44 (d, 1H, J_(HH)=8.4 Hz), 5.56 (d, 1H,J_(HH)=8.4 Hz), 7.29˜7.25 (m, 3H), 7.22˜7.11 (m, 6H), 6.98˜6.91 (m, 2H),6.76 (t, 1H, J_(HH)=7.2 Hz), 6.51 (t, 1H, J_(HH)=7.2 Hz), 6.31 (d, 1H,J_(HH)=7.2 Hz), 6.27 (t, 1H, J_(HH)=7.2 Hz), 5.69 (d, 1H, J_(HH)=7.6Hz), 5.57 (d, 1H, J_(HH)=15 Hz), 5.39 (d, 1H, J_(HH)=16 Hz), 5.25 (d,1H, J_(HH)=15 Hz), 3.30 (s, 3H), 3.25 (s, 3H).

EXAMPLE 7a [Ir(dfbmb)₂(fptz)] (7a)

Compound 7a was obtained in 49% by the similar procedure described forcompound 6a. The reaction temperature was changed from 130° C. toreflux. Purification was conducted by silica gel column chromatographyusing CH₂Cl₂/hexane (2:1) as eluent.

Spectra data of compound 7a : MS (FAB), 921(M⁺), 707 (M⁺-fptz). 1 H NMR(500 MHz, d₆-acetone, 298 K): δ 9.42 (d, 1H, J_(HH)=5.5 Hz), 8.03 (td,1H, J_(HH)=7.8, 1.5 Hz), 7.96 (d, 1H, J_(HH)=7 Hz), 7.89 (d, 1H,J_(HH)=8.0 Hz), 7.79 (d, 1H, J_(HH)=8.0 Hz), 7.61 (td, 1H, J_(HH)=7.8,1.5 Hz), 7.44 (d, 2H, J_(HH)=8.0 Hz), 7.39˜7.33 (m, 2H), 7.28 (t, 2H,J_(HH)=8.0 Hz), 6.73 (d, 1H, ²J_(HH)=15.0 Hz), 6.56 (td, 1H,J_(HF)=10.5, J_(HH)=3.0 Hz), 6.41 (td, 1H, J_(HF)=10.5, J_(HH)=3.0 Hz),6.12 (d, 1H, J_(HH)=16.5 Hz), 5.99 (d, 1H, J_(HH)=15.0 Hz), 5.75 (dd,1H, J_(HF)=10.8, J_(HH)=2.0 Hz), 5.46 (d, 1H, ²J_(HH)=16.5 Hz), 5.23(dd, 1H, J_(HF)=10.8, J_(HH)=2.0 Hz), 3.47 (s, 3H, Me), 3.38 (s, 3H,Me). ¹⁹F NMR (470 MHz, d₆-acetone, 298 K): δ −64.0 (s, 3F), −115.5 (s,1F), −117.0 (s, 1F), −117.8 (s, 1F), −118.4 (s, 1F).

EXAMPLE 7b [Ir(dfbmb)₂(bppz)] (7b)

Compound 7b was obtained in 32% by the similar procedure described forcompound 6a. But the temperature of the reaction was changed from 130°C. to reflux. Purification was conducted by silica gel columnchromatography using CH₂Cl₂/hexane (2:3) as eluent.

Spectra data of compound 7b: MS(FAB), 976(M⁺), 707 (M⁺-bppz). ¹H NMR(400 MHz, d₆-acetone, 298 K): δ 9.16 (d, 1H, J_(HH)=6.4 Hz), 7.87 (d,1H, J_(HH)=8.4 Hz), 7.81˜7.77 (m, 2H), 7.44˜7.42 (m, 3H), 7.38˜7.32 (m,2H), 7.29˜7.24 (m, 2H), 7.03˜7.00 (m, 2H), 6.53 (td, 1H J_(HF)=11.2,J_(HH)=3.2 Hz), 6.37 (td, 1H J_(HF)=10.4, J_(HH)=2.8 Hz), 6.08 (d, 1H,J_(HH)=16 Hz), 5.93 (d, 1H, J_(HH)=14.4 Hz), 5.72 (d, 1H, J_(HF)=10.4Hz), 5.43 (d, 1H, J_(HH)=16 Hz), 5.22 (d, 1H, J_(HF)=10.8 Hz), 3.44 (s,3H), 3.38 (s, 3H), 1.31 (s, 9H). ¹⁹F NMR (470 MHz, d₆-acetone, 298 K): δ−118.8 (s, 1F), −118.3 (s, 1F), −117.3 (s, 1F), −116.0 (s, 1F), −60.5(s, 3F).

EXAMPLE 7c [Ir(dfbmb)₂(bptz)] (7c)

Compound 7c was obtained in 45% by the similar procedure described forCompound 6a. But the temperature of the reaction was changed from 130°C. to reflux. Purification was conducted by silica gel columnchromatography using CH₂Cl₂/hexane (3:2) as eluent.

Spectra data of compound 7c: MS (FAB): 977 (M⁺), 707 (M⁺-bptz). ¹H NMR(400 MHz, d₆-acetone, 298 K): δ 9.27 (d, 1H, J_(HH)=6 Hz), 7.93 (d, 1H,J_(HH)=1.6 Hz), 7.89 (d, 1H, J_(HH)=8.4 Hz), 7.80 (d, 1H, J_(HH)=7.6Hz), 7.64 (dd, 1H, J_(HH)=6.0, 2.4 Hz), 7.45 (t, 2H, J_(HH)=7.8 Hz),7.39˜7.34 (m, 2H), 7.31˜7.26 (m, 2H), 6.67 (d, 1H, J_(HH)=15 Hz), 6.57(td, 1H, J_(HF)=10.8, J_(HH)=2.8 Hz), 6.41 (td, 1H, J_(HF)=10.4,J_(HH)=2.4 Hz), 6.12 (d, 1H, J_(HH)=16 Hz), 5.98 (d, 1H, J_(HH)=15 Hz),5.75 (d, 1H, J_(HF)=12.8 Hz), 5.44 (d, 1H, J_(HH)=16 Hz), 5.23 (d, 1H,J_(HF)=10.4 Hz), 3.44 (s, 3H), 3.39 (s, 3H), 1.33 (s, 9H), ¹⁹F NMR (470MHz, d₆-acetone, 298 K): δ −118.4 (s, 1F), −117.8 (s, 1F), −117.0 (s,1F), −115.7 (s, 1F), −63.9 (s, 3F).

EXAMPLE 8a [Ir(fbmb)₂(fptz)] (8a)

Compound 8a was obtained in 36% by the similar procedure described forCompound 6a. Purification was conducted by silica gel columnchromatography using CH₂Cl₂/hexane (1:1) as eluent.

Spectra data of compound 8a: MS (FAB): 884 (M⁺), 670 (M⁺-fptz). ¹H NMR(400 MHz, d₆-acetone, 298 K): δ 9.33 (d, 1H, J=5.6 Hz), 8.01˜7.97 (m,2H), 7.87 (d, 1H, J=8 Hz), 7.77 (d, 1H, J=8 Hz), 7.59˜7.56 (m, 1H),7.44˜7.41 (m, 3H), 7.35˜7.22 (m, 5H), 6.98 (d, 1H, J=14.4 Hz), 6.64(ddd, 1H, J_(HF)=9.0, J_(HH)=8.4, 2.8 Hz), (ddd, 1H,J_(HF)=9.0,J_(HH)=8.4, 2.8 Hz), 5.91 (dd, 1H, J_(HF)=14.4 Hz, J_(HH)=2.8Hz), 5.82˜5.71 (m, 2H), 5.60 (d, 1H, J=14.4 Hz), 5.35 (dd, 1H,J_(HF)=14.4 Hz, J_(HH)=2.8 Hz), 3.45 (s, 3H, Me), 3.38 (s, 3H, Me).

EXAMPLE 8b [Ir(fbmb)₂(bppz)] (8b)

Compound 8b was obtained in 33% by the similar procedure described forCompound 6a. Purification was conducted by silica gel columnchromatography using CH₂Cl₂ as eluent.

Spectra data of compound 8b: MS (FAB): 940 (M⁺), 670 (M⁺-bptz). ¹H NMR(400 MHz, d₆-acetone, 298 K): δ 9.19 (d, 1H, J_(HH)=6.2 Hz), 7.93 (d,1H, ⁴J_(HH)=2.4 Hz), 7.86 (d, 1H, J_(HH)=8.4 Hz), 7.76 (d, 1H,J_(HH)=8.4 Hz), 7.62 (dd, 1H, J_(HH)=6.2, 2.4 Hz), 7.44˜7.39 (m, 3H),7.34˜7.21 (m, 5H), 6.96 (d, 1H, ²J_(HH)=14.4 Hz), 6.63 (ddd, 1H,J_(HF)=9.0, J_(HH)=8.4, 2.8 Hz), 6.45 (ddd, 1H, J_(HF)=9.0, J_(HH)=8.4,2.8 Hz), 5.89 (dd, 1H, J_(HF)=14.4, J_(HH)=2.8 Hz), 5.81˜5.70 (m, 2H),5.59 (d, 1H, 2J_(HH)=14 Hz), 5.35 (dd, 1H, J_(HF)=14.4 Hz, J_(HH)=2.8Hz), 3.39 (s, 3H, Me), 3.43 (s, 3H, Me), 1.33 (s, 9H). ¹⁹F NMR (470 MHz,CDCl₃, 298 K): δ −63.3 (s, 3F), −118.0 (s, 1F), −119.5 (s, 1F).

Selected photophysical data of complexes 1a-8b prepared in Examples1a-8b, were measured in degassed CH₂Cl₂ solution at RT and are shown inTable 1.

TABLE 1 abs. λ_(max)/nm (ε × 10⁻³) em λ_(max)/nm Φ (%) τ_(obs)/μs 1a 269(21.2), 367 (1.3) 435, 458 6 0.17 1b 261 (23.0), 368 (1.8) 460 10 0.101f 276 (43.8), 343 (8.5) 464, 488 45 2.77 1g 267 (28.1), 340 (5.6) 456,480 20 1.23 2b 261 (22.3), 287 (14.7), 371 (1.8) 460 9 0.15 3b 261(24.0), 284 (16.1), 372 (1.4) 460 11 0.08 4b 261 (21.8), 284 (15.4), 370(1.4) 457 4 0.07 5a 267 (23.5), 314 (8.7), 360 (1.6) 462, 485 — — 5b 260(29.5), 312 (9.7), 351 (2.2) 427, 451 — — 6a 302 (30.4), 326 (20.7), 396(1.2) 499 60 0.78 7a 293 (23.7), 316 (26.5), 363 (1.8) 458 73 0.38 7b295 (29.6), 320 (31.5), 359 (2.5) 450, 477 30 0.94 7c 292 (45.9), 320(36.7), 361 (5.9) 434, 455 30 0.29 8a 297 (35.2), 321 (30.2), 372 (2.0)509 35 0.48 8b 298 (25.0), 322 (22.1), 363 (1.8) 460 22 0.22

EXAMPLE 12 [Ir(bdpp)(fppz)₂] (9)

A mixture of IrCl₃.3H₂O (211 mg, 0.6 mmol) and benzyldiphenylphosphine(166 mg, 0.6 mmol) was dissolved in degassed 2-methoxyethanol and heatedto 120° C. overnight, giving transparent yellow solution. After cooledto room temperature, fppzH (269 mg, 1.26 mmol) and Na₂CO₃ (636 mg, 6.0mmol) was added into the solution. The reaction mixture was refluxed foranother 24 h. After cooling to room temperature, reaction was quenchedby addition of excess water. The resulting precipitate was collected byfiltration and washed by ice MeOH, diethyl ether, then dried undervacuum. The product was purified by silica-gel column chromatographyusing EA/hexane (1:4) as eluent. Recrystallization in mixedCH₂Cl₂/hexane solution at room temperature gave xx as white powder (48mg, 0.05 mmol, 8.4%).

Spectra data of 9. ¹H NMR (500 MHz, CDCl₃, 294K): δ 7.70 (t, J=7.5 Hz,1H), 7.63 (t, J=7.6 Hz, 1H), 7.53 (d, J=8.0 Hz, 2H), 7.37-7.32 (m, 4H),7.18 (t, J=7.8 Hz, 2H), 7.15-7.13 (m, 1H), 7.10-7.05 (m, 2H), 6.97-6.95(m, 4H), 6.88-6.77 (m, 5H), 6/75 (s, 1H), 6.72 (s, 1H), 4.99 (t, J=13.5Hz, 1H), 3.65 (t, J=14.0 Hz, 1H). ¹⁹F{¹H} NMR (470 MHz, CDCl3, 294K): δ−60.37 (s, 3F), −60.66 (s, 3F). ³¹P{¹H} NMR (202 MHz, CDCl₃, 294K): δ11.53 (s, 1P).

EXAMPLE 13 [Ir(dfbmb)(fptz)₂] (10)

A mixture of 3-trifluoromethyl-5-(2-pyridyl) pyrazole (fppzH) (0.13 g,0.61 mmol) and IrCl₃.3H₂O (0.10 g, 0.29 mmol) in DGME (20 mL) wasrefluxed for 4 hours under N₂. The mixture was then cooled to roomtemperature, and 0.11 g (0.32 mmol)1-(2,4-difluorobenzyl)-3-methyl-benzimidazolium bromide (dfbmbH₂Br) and0.13 g (0.56 mmol) Ag₂O were added. The resulting mixture was refluxedfor 12 hours, and 20 mL water was added after cooling the solution to RTand removing some DGME solvent, the yellow precipitate was collected byfiltration. The precipitate was separated using silica gel columnchromatography (CH₂Cl₂), giving a bright blue emissive complex (0.032 g,0.037mmol, 13%).

Spectral data of 10: MS (FAB, ¹⁹²Ir): 874 [M⁺+1]. ¹H NMR (400 MHz,d₆-acetone, 294 K): δ 8.18 (d, J_(HH)=8.0 Hz, 1H), 8.04˜7.95 (m, 3H),7.85 (d, J_(HH)=7.5 Hz, 1H), 7.63 (s, 1H), 7.52 (d, J_(HH)=8.5 Hz, 1H),7.38˜7.35 (m, 2H), 7.32˜7.27 (m, 2H), 7.23 (t, J_(HH)=6.0 Hz, 1H), 7.20(s, 1H), 7.10 (d, J_(HH)=5.5 Hz, 1H), 6.44 (td, J_(HH)=9.5, 2.0 Hz, 1H),6.17 (d, J_(HH)=15.0 Hz, 1H), 5.94 (s, 1H, br), 5.86 (d, J_(HH)=14.5 Hz,1H), 3.66 (s, 3H). ¹⁹F NMR (470 MHz, d₆-acetone, 294K): δ −118.9 (s,1F), −117.3 (s, 1F), −60.9 (s, 3F), −60.8 (s, 3F). Anal. Calcd. forC₃₃H₂₁F₈IrN₈: N, 12.82; C, 45.36; H, 2.42. Found: N, 12.03; C, 45.45; H,2.02.

1. A phosphorescent tris-chelated transition metal complex comprising i)two identical non-conjugated cyclometalated ligands being incorporatedinto a coordination sphere thereof with a transition metal, and oneligated chromophore being incorporated into the coordination sphere; orii) one non-conjugated cyclometalated ligand forming a coordinationsphere thereof with a transition metal, and two ligated chromophoresbeing incorporated into the coordination sphere, wherein the transitionmetal is iridium, platinum, osmium or ruthenium, and the ligatedchromophore possesses a relatively lower energy gap in comparison withthat of the non-conjugated cyclometalated ligand, the latter afforded aneffective barrier for inhibiting the ligand-to-ligand charge transferprocess, so that a subsequent radiative decay from an excited state ofthese transition metal complexes will be confined to the ligatedchromophore.
 2. The complex of claim 1, wherein the energy gap of theligated chromophore is for blue, green or red emission.
 3. The complexof claim 1, wherein the metal is iridium.
 4. The complex of claim 3,wherein the complex is represented by the following formulas Ia, Ib andtheir stereo isomers:

wherein the non-conjugated cyclometalated ligands are represented by Cand N linked with an arch, and has a formula of Ar₁—C(R₁R₂)—Ar₂, whereinAr₁ is aromatic ring, Ar₂ is N-heterocyclic ring, R₁ and R₂independently are H or methyl, wherein C in the formulas Ia and Ib is acarbon atom contained in Ar₁ and N in the formulas Ia and Ib is anitrogen atom contained in Ar₂; the ligated chromophore is presented bythe L and X linked with an arch, and has formula of Ar₃—Ar₄, wherein Ar₃and Ar₄ independently are an aromatic ring or N-heterocyclic ring, orAr₃—Ar₄ together are

wherein L is N or O, and X is C, N or O.
 5. The complex of claim 3,wherein the complex is represented by the following formulas IIa, IIband their stereo isomers:

wherein the non-conjugated cyclometalated ligands are represented by Pand C linked with an arch, and has a formula of Ar₅—C(R₁R₂)—P(Ar₆Ar₇),wherein Ar₅, Ar₆ and Ar₇ independently are an identical aromatic ring ordifferent aromatic rings, R₁ and R₂ independently are H or methyl,wherein C in the formulas IIa and IIb is a carbon atom contained in Ar₅;the ligated chromophore is presented by the L and X linked with an arch,and has formula of Ar₃—Ar₄, wherein Ar₃ and Ar₄ independently are anaromatic ring or N-heterocyclic ring, or Ar₃—Ar₄ together are

wherein L is N or O, and X is C, N or O.
 6. The complex of claim 4,wherein the non-conjugated cyclometalated ligands are

wherein n is an integer of 1-3.
 7. The complex of claim 6, whereinpositions of F and C_(n)F_(2n+1) groups on phenyl rings of thenon-conjugated cyclometalated ligands are varied, and n is
 1. 8. Thecomplex of claim 7, wherein F and C_(n)F_(2n+1) groups on phenyl ringsof the non-conjugated cyclometalated ligands are independently replacedby CN group.
 9. The complex of claim 5, wherein the non-conjugatedcyclometalated ligands are

wherein Ph is phenyl, and n is an integer of 1-3.
 10. The complex ofclaim 9, wherein positions of F and C_(n)F_(2n+1) groups on phenyl ringsof the non-conjugated cyclometalated ligands are varied, and n is
 1. 11.The complex of claim 10, wherein F and C_(n)F_(2n+1) groups on phenylrings of the non-conjugated cyclometalated ligands are independentlyreplaced by CN group.
 12. The complex of claim 4, wherein the ligatedchromophores are

wherein Ph is phenyl.
 13. The complex of claim 5, wherein the ligatedchromophores are

wherein Ph is phenyl.
 14. The complex of claim 3, wherein the complex isrepresented by the following formulas IIIa, IIIb and their stereoisomers:

wherein the non-conjugated cyclometalated ligands are represented by Cand C linked with an arch, and has a formula of Ar₈—C(R₁R₂)—Arg, whereinAr₈ is aromatic ring, Ar₉ is N-heterocyclic carbene, R₁ and R₂independently are H or methyl, wherein C in the formulas IIIa and IIIbis a carbon atom contained in Ar₈ and Ar₉; the ligated chromophore ispresented by the L and X linked with an arch, and has formula ofAr₃—Ar₄, wherein Ar₃ and Ar₄ independently are an aromatic ring orN-heterocyclic ring, or Ar₃—Ar₄ together are

wherein L is N or O, and X is C, N or O.
 15. The complex of claim 14,wherein the non-conjugated cyclometalated ligands are

wherein n is an integer of 1-3.
 16. The complex of claim 15, whereinpositions of F and C_(n)F_(2n+1) groups on phenyl rings of the twoidentical non-conjugated cyclometalated ligands are varied, and n is 1.17. The complex of claim 16, wherein F and C_(n)F_(2n+1) groups onphenyl rings of the non-conjugated cyclometalated ligands areindependently replaced by CN group.
 18. The complex of claim 14, whereinthe ligated chromophores are

wherein Ph is phenyl.